Continuous processes for solvent extraction of oil from oil-bearing materials and refinement of the residual solid product



1951 M. BoNoTTo 2,567,179

CONTINUOUS PROCESSES FOR SOLVENT EXTRCTION OF OIL FROM OIL-BEARING MATERIALS AND REFINEMENT OF THE RESIDUAL SOLID PRODUCT Filed July 23, 1945 Sept atented Sept. il, 19.5.1

CONTINUOUS PROCESSES FOR SOLVENT EXTRACTION OF OIL FROM OIL-BEAR- ING MATERIALS AND REFINEMENT OF THE RESIDUAL SOLID PRODUCT Michele Bonotto, Princeton, N. J. Application July 23,1945, Serial No. 606,638

4 Claims.

This invention relates to'improvements in con- -tinuous processes for solvent extraction of oil from oil-bearing materials and refinement of the residual solid product.

One of the objects of this invention is to provide a process andapparatus in which oil-bearing material is in a continuous process extracted by a. liquid solvent in an extractor at relatively low extracting temperatures, and preferably with liquid gasoline having a boiling range between 147 F. and 205 F.; the extracted solid product is then fed directly from the extractor into a solvent eliminator known in this art as a direct dryer and is there preheated by solvent vapors, preferably obtained by superheating the used solvent vapors from the system, to a temperature above the condensation temperature of steam, whereupon such preheated material is subjected to refining and final elimination of solvent by blown steam either in a section of the same direct dryer" used to blow said solvent vapor `or in a separate similar apparatus.

My invention thus results in eliminating the conventional step, and the extensive apparatus employed therein, of initially preheating and predrylng such material by indirectly applied heat or through the use of intermediate heat-transferring surfaces.

Another object of my invention'is to speed up and greatly reduce the time required to process or reflne solvent-extracted oil-bearing material and furthermore to refine a solid proteid product of better quality from which the oil and solvent will be completely eliminated and in which the proteids will be maintained in undenaturate and uninjured condition without loss of the natural moisture content. l

In continuous extraction systems of the prior art, the use of heaters of indirect type has heretofore always been considered necessary for the purpose of elevating the temperature of solventextracted products, so as to preheat the same from the relatively low temperature at which they leave the solvent-extraction apparatus, to the relatively high temperature of 200" F. or 212 F. necessary `to control or avoid condensation of steam in solvent eliminators or direct steam dryers.

During preheating treatment in anindlrect dryer of the conventional type, the extracted meal is'conveyed in a series of long horizontallydisposed steam-jacketed tanks for a considerable time period and subjected to agitation by the conveyor devices or to a lifting and tumbling operau,... 1....l s +A immantiwannlied heat in. ordery to eliminate part of the solvent while the material is being moved forwardly in such devices.,

- During this movement part of the natural mois-- ture contained in theextracted meal is also evaporated with the solvent and passes off with the solvent vapor while the temperature of the ma terial rises due to the heat transmitted through,v

the jacketed walls of the apparatus.

It has been found that such agitation, lifting; or tumbling operation, as well as the reducing of the natural moisture of the solvent extracted.

f tracted flaxseed and cotton-seed, a very high percentage of dust is created and a part of this dust is of such neness that it is carried out of the condensers with the condensate, thus creating difficulties in the solvent storage tanks where such dust accumulates, and heretofore, in order to avoid or partially take care of `the above deleterious conditions, it has been the practice to interpose between the vapor-outlet of the indirectV dryer and the condenser one or more dust collectors of the conventional type. These dust collectors usually comprise a jacketed expansionchamber followed by a water-spraying chamber where the dust is collected and carried out with the Water which is sprayed in fine subdivision at a temperature above the boiling point of the solvent so as to avoid condensation of the same. Notwithstanding the above, some solvent and some material in dust form are always lost in the operation of these dust collectors.

By the use of my present invention, the step in the system of employing indirect dryers for driving out part of the solvent with indirect heat and also initially preheating the material is completely eliminated with the result that the use of such indirect drying apparatus with all the disadvantages hereinabove specified is avoided, and also all the accessories used therewith, such asy motors,idrives, conveyors, dust collectors, etc. are

also elinmated with the accompanying economy of apparatus, space and expense. y

so1vent-eliminating because of the fact that the* heated mass of extracted material leaves the extractor at temperatures well below, 212i F., and. i1 such mass were immediately introduced into. a

direct steam dryer, the condensation' of 'suchvdilr rect steam in the mass would create serious djculties which vary somewhat 'according totheV type and quality of material under direct steam,L

treatment. For example, solvent-extracted flaxseed will, under such direct steam treatment;ag-A glutinate in a mass of the consistency of a pouloffsu'ch material t'yeitett Steam treatment Anthetobjet' of myinventiori is to'economize thesteam c mveritimfallyused in the process and:

apparatus for drying and preheatingl solvent-ex: trttetedmaterial'through' indirettlyappuei neat, aii'd'to v'slibstitute therefor aprocess andiappara-'-y tus which not onlyavoidfs the dii'lic'ulties and dis-Y advantages inherent in the use bfsuhprior'process'v` and apparatus but produces" a" product'ofy bette duality." v

With these and other objects lthe invention comprisesnthe st'p's iriithe method` and thecom'- inthe performance of the"functioris andthe'ac;

and comprises `ii"`oiie "O17 its'ladaptations'the; species" or^preferred form illustrated inlthe acl-r companying drawing." 'U

A"Ihe''gure of tndrawing is a diagrammatic View embodying a preferred form of apparatus.

"Referring n ow to the accompanying drawingin acotardance'withv theprfrred form of' my inivention,` I 4Vfeed oillbeajring material 'which may. ise the mealofa 'suitable oil-bearingseed` oshscra'ps Afrom a conventionalhopper? Land. pass'"the'saine through a solventLextr'action col-` l2y 'preferably of the" typesh'own'and. 'clef scribed -in'.'my'patents` numberedV '2,158,782 ror. 2,206,595." In vthis"extractor 2, a liquid. solventv usually comprising gasolinefwith. a boiling 'range' between`1471t"205;s. is'obtainedfrom a soif vent' storage tank'5`and is .heated to" a degreebeflow fits" boiling pointl by heater 3. and pumpedbypump?! through the massiin'counterecurrent:to; thepassage thereof, 'whereupon' the extracted.A product leaves the' 'extractioncolumnrat approxi'- mately 145? F. It is now necessary to eliminate:

th'solvent and the final traces ofi such solvent' fromthislextracted product, Vand to accomplish this result with ther least'possible injury to .the protei'cls and without denaturation' thereof. This is .most advantageously and'ecnornically accomL plishedV by subjecting the extracted product cpndensation temperature Q'f the Steam usedm.

order to avoid the. dimpultiesvliereiriabsye isaec d flle.

fied, and, as aforesaid, this has been heretofore done in two steps, first, by the use of indirect dryers which resulted 4in injury to the product by the agitating, conveying or lifting and tumbling as Well as the increased time period to which such material is subjected to heat and with the other disad tages and diiiiculties also specified abt, i n, tqndby the' Ibietti r1orthe mater'lar to the solvent-eliminating ation of steam directly blown into the mass in a direct dryer.

"In accordance with my present invention, I immediatelyL a continuous process subject the exvtr ,tedj irlater 4lHtL the temperature-elevating stpof, bio o lvent vapors direcuy into the mass at! atemperature above (the condensation lpointl oft steam, For this purpose, I connect directly thee`Xt1actor 2 by a simple conductor 2c with-a vapQr-blowing apparatus 1 and utilize in a section l provided therefor in they said vaporblowig'iapparatus or direct dryer tank 'Va part of the vapors of an oil-extracting solvent, and preferablyfthe supe'rhea'tedvap'orsofithersolvnt Which"has theret'o'fo'relbeen us'ediintheextractor;

2 "Such" solvent" vapors 'mayv 'bei produced: in f' am.

apparatus specially providedfo the p'rposesuch; as" the `solvent" vaporizerA 8," but, in thefpreierrd form of' my invention; thesjej 'vaporsi are f'takenp froml Vafsuitable section' off the conventional:dise.'-I tilling r apparatus:in'which the niicella is treat' to recover the "'oil. 'Asi' shown', theimicella iszcor'rer ducted fromthe 'extraction"column:- 2 "byfc oridugifn 2&5 toa"` micella 'tanl'z "and thence 'c'ondictet through various apparatusto" a "calaridria?4 IA-B-andf expansion chamberif "1."1 f'frorn which* part of :the: vapors are passed-throughthe blower"compressoriv I Bia'nd conduit` 119 'to aivapor-superheateziliandL thence" toi the directdryer teinkflx Asshowmithe` micella is'con'ductedby conduit;V Rei-ato puinpfil;v which pumps Tfthel micellathrough conduite 10E;

thence VAthrough rotarnte l,landconcluittlila to', a condenser' |52 n which'lpartlroftlieliquidffsolvent contained in f'th'e"nicellasls"preheated.--Tl1e mie: cella; is then conductejdftthrug'h "conduit li|4, heater IA E-Tto" the Calandria I Brand vapozvchamber Y they" are 'ondictedandi Blown' as aforesaid.

into'ithe said section liaof thel'directdryerztanlftr. In` Vthis sectionV '1;'11 the .'proteidproductisy heated directlyby'ithe vap'orized;'solvent"and:brtlghtto: a" "heat "of app'roxinatelyzZI09+22Q .Infiitil'l ing."tiese' vaposT preferably, bytheruse of theA superheater 2.0? lac'e'dbefore" the vsolventI vapors i enter "the" "dryeririse the "temperature: thereof: according to chemical and physical .chara 1f; teristic'stoflthe' 'solventi tdeapproximatelyzZSOgrto 240? These.' vapors at'fthis relatively highztemf'; peature arefa'st 'statedrinjectedfdirectlyi into the.; product i through" a? sett" or:v s'eriesi `of A-lwer noz'zles fTh'enoltzles are? of? the type :shown atfArgl: iin, myfPate'nt #2,199,255? The use off'theseffSuperfheatedfvapors. in 'direct Vconta'ctlfv/ith the fextI'QQL- passed. fromzthefextractor-iat approximately; 149i Willa-cause said; temperatureot the extracted marterial to be elevated or raised to approrimglitely?I 2.1m, which-,comprises mass Qr-iprgdii en pe at rethatis 't aueqllllt dit4 t. steamirsaimentt; odi @aiment Qi my intention, I' direc dryer t il r n fIl o *ants and I preferably inject superheated steam through said set or series of nozzles directly into the material in the tank 1. 'I'his tank I preferably is constructed substantially as shown in my Patent #2,199,255 except as herein specified. When solvent vapors for use in my dryer are taken from the vaporizing portion of the distilling apparatus where the micella is treated to recover the oil, a substantial economy will result because the heat utilized to elevate or raise the temperature of the mass or product would otherwise pass into the water of the condensers. When so utilizing such vapors and steam in a common direct-dryer these vapors will rise in the material and will then join and commingle with the superheated steam and pass 01T to a conventional condenser 2|. In the system shown, the separated oil passes from the vaporizer chamber I1 through conduit 22 and heater 23 to a stripper column 24, whereupon the last traces of solvent are vaporized and pass with the steam which is injected at the lower end of the column through conduit 25 to the condenser 26 and, as shown, both condensers 2| and 26 are connected to a water separator 21 from which the solvent may be conducted by conduit 28 to the pure solvent storage tank 5.

It will be understood that by the us'e of solvent vapors from the micella treating section of the system, applicant avoids the necessity of independently vaporizing solvent to procure these vapors and this results in very considerable economy in the system.

In case no micella is under distillation, I may conduct by suitably valved conductor 29 pure solvent from the solvent-storage tank to the preheater I5 and calandria I6 where it is vaporized and then passes through the expansion chamber I1, blower-compressor I8 and conduit I9 to the preheater 20, nozzles 'Il and into the product in the tank 1.

'I'he ywords direct-dryer as used herein are intended to refer to apparatus in which the liquid solvent that is still contained in the extracted material is removed in vapor form by direct application of steam to the mass. l

It will be understood that any part of the solvent vapors that may be condensed in the solid residual mass will be eliminated together with the original liquid solvent by the blowing of the steam therethrough.

Having described my. invention, I claim:

1. The process of solvent extraction and relining of vegetable and animal substances consisting in subjecting the raw material to oil extraction with a liquid solvent having a boiling point less than the condensation point o1 steam by continuously moving the raw material through an extraction column and causing the temperature of the residual meal product to be lower than the condensation temperature of steam, feeding the residual product in an operation continuous with said extraction from the lower end of said extraction column into a direct-dryer, elevating the temperature of the meal product to a point approximating the condensation temperature of steam by blowing vapors of a solvent similar to that employed in the subjection of material to oil extraction heated to a temperature above the condensation point of steam directly into said residual product in such continuous operation to bring said product to a temperature approximating said steam condensation point, and then blowing steam directly into said vapor-heated product to eliminate by steam distillation the solvent therefrom.

2. The process claimed in claim 1 in which the residual material is moved in an upward direction in an upright direct-dryer, solvent vapor is blown into said residual material at one level, the steam is blown at a higher level than the solvent vapors and both vapor and steam move together in the same direction as the residual material.

3. The process of solvent extraction and rening oi vegetable and animal substances consisting in subjecting the raw material to oil extraction with a liquid solvent having a boiling point less than the condensation point of steam by continuously moving the raw material through an extraction column and causing the temperature of the residual meal product to be lower than the condensation temperature of steam, feeding said residual material in an operation continuous with said extraction directly from the lower end of said extraction column to an upright directdryerrand moving said material therein in a substantially vertical direction, elevating the temperature of the meal product to a point approximating the condensation temperature of steam by blowing at a level above the feeding inlet vapors of a solvent distilled lfrom micella obtainedv in the extraction step, heated to a temperature above the condensation point of steam directly into said residual product to bring said product in such continuous operation to a temperature approximating said steam condensation point, and then blowing, directly into said vapor-heated product at a level of the moving material higher than that at which said vapor is blown, steam to eliminate by steam distillation the solvent therefrom and to cause discharging movements by buoyancy of both vapor and steam in the direction of movement of the material.

4. The process as claimed in claim 3 in which the directly blown solvent vapors are heated to approximately 240 F. and the residual process product is heated to approximately 212 F. prior to subjecting the same to blown steam.

MICHELE BONOTTO.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

1. THE PROCESS OF SOLVENT EXTRACTION AND REFINING OF VEGETABLE AND ANIMAL SUBSTANCES CONSISTING IN SUBJECTING THE RAW MATERIAL TO OIL EXTRACTION WITH A LIQUID SOLVENT HAVING A BOILING POINT LESS THAN THE CONDENSATION POINT OF STEAM BY CONTINUOUSLY MOVING THE RAW MATERIAL THROUGH AN EXTRACTION COLUMN AND CAUSING THE TEMPERATURE OF THE RESIDUAL MEAL PRODUCT TO BE LOWER THAN THE CONDENSATION TEMPERATURE OF STEAM, FEEDING THE RESIDUAL PRODUCT IN AN OPERATION CONTINUOUS WITH SAID EXTRACTION FROM THE LOWER END OF SAID EXTRACTION COLUMN INTO A DIRECT-DRYER, ELEVATING THE TEMPERATURE OF THE MEAL PRODUCT TO A POINT APPROXIMATING THE CONDENSATION TEMPERATURE OF STEAM BY BLOWING VAPORS OF A SOLVENT SIMILAR TO THAT EMPLOYED IN THE SUBJECTION OF MATERIAL TO OIL EXTRACTION HEATED TO A TEMPERATURE ABOVE THE CONDENSATION POINT OF STEAM DIRECTLY INTO SAID RESIDUAL PRODUCT IN SUCH CONTINUOUS OPERATION TO BRING SAID PRODUCT TO A TEMPERATURE APPROXIMATING SAID STEAM CONDENSATION POINT, AND THEN BLOWING STEAM DIRECTLY INTO SAID VAPOR-HEATED PRODUCT TO ELIMINATE BY STEAM DISTILLATION THE SOLVENT THEREFROM. 